ステンレス鋼の種々なカソード電位下における低ひずみ速度引張試験

概要

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The corrosion behavior of metal is closely related to its polarization behavior in a corrosive solution. The polarization behavior is said to be useful for understanding pitting corrosion or stress corrosion cracking and hydrogen embrittlement in particular. In this study, in order to elucidate the relation between the cathodic potential and mechanical properties, the slow strain rate tension tests were carried out under various cathodic potentials. The main results obtained are summarized as follows. (1) Under tensile stress, the pitting initiation potentials of SUS 430 and SUS 304 shifted towards the less-noble side but SUS 316 did not show such a shift. The hydrogen overpotential of the testing materials shifted towards the noble side with increasing applied stress in the elastic region. Consequently, the hydrogen evolution reaction in 3%NaCl , solution was promoted by the presence of stress. (2) In the case of SUS 430, the degradation of mechanical properties (reduction in size and time to fracture, etc.) became more pronounced with increasing setting cathodic potential, but in the case of molybdenum-bearing SUS 316, the degradation of mechanical properties was less than the other materials. The above phenomenon can be also understood from the observation results obtained by S. E. M.. Such a correlation between the mechanical properties and electrochemical properties became more pronounced at slower strain rates.
1987-04-15